The present invention relates to chucks and particularly to improvements in the collets for use with such chucks. Such improved chuck collets are particularly useful with rough workpieces for roughing operations, although also useful for finishing operations.
Different modifications of the invention are adapted to support workpieces of different contours either externally or internally, i.e. engaging either the O.D. or I.D. of the workpieces.
In general, the chuck collet comprises a pair of axially spaced first and second surfaces adapted to engage corresponding spaced surfaces on the clutch body and have engaging cam surfaces to effect radial movement of the workpiece. In particular, according to the present invention, the grip engaging portions of the collet are in the form of a plurality of separate, annular jaw segments. Such jaw segments are connected to the other collet surface, which in the preferred embodiment is an annular base member and in a modification are other jaw segments, by a plurality of elongated spring elements or members. In the preferred embodiment, the connecting members are in the form of spring steel rods and in another modification the connecting members are in the form of flat spring leafs. In another modification, a single flat leaf spring of calculated width for proper flexing is employed to interconnect the jaws with the collet base. The rods have been found to be more advantageous.
The interconnecting members, in all of the three modifications disclosed, are separate elements from the gripping jaws and the collet base support. This has the manufacturing and economical advantages over prior chuck collets of being able to select different materials for these parts and not compromise the functions of the respective parts. For example, the gripping jaws can be made much harder, as separate elements, e.g., up to 50-60 Rock. C, or of solid carbide.
This means that material for the rods or leafs may be selected independently of the jaw material to give the best results and with greater economy. They may be of selected spring steel, having the optimum flexibility over a long range and optimum fatigue life. This accomplishes a greater range in handling rough workpieces as well as a longer flex life. A further advantage is better chip clearance.